Narrow (≈4 meV) inhomogeneous broadening and its correlation with confinement potential of pyramidal quantum dot arrays

The inhomogeneous broadening in the luminescence spectra of ordered arrays of pyramidal GaAsAlGaAs semiconductor quantum dots (QDs) was studied as a function of the dot size. Dot arrays with inhomogeneous broadening as small as 4.1 meV and a corresponding ground state to first excited state transition separation of 28 meV were obtained. By evaluating the QD energy levels using a multiband kp model, the authors estimated that the observed inhomogeneous broadening corresponds to dot height fluctuations of about 1-2 ML across the array.